This specification relates to editing electronic documents in a collaborative manner using a web-based communication system. Conventional web-based systems allow multiple users to collaborate on a particular type of document. For example, existing online word processor systems allow multiple users to collaborate on a word processing document. In such systems, a word processing client application communicates with a server system that is configured for managing word processing documents. The client application can refresh the document on the client device by requesting the latest version of the document from the server. The client application can also modify the word processing document and send the updated word processing document to the server. When the server receives the updated document, the server can store the updated word processing document as an updated document version.